Barcelona coach Tito Vilanova is expected to step down after it was reported that a tumour removed last year had returned.
Barcelona have not made an official announcement regarding Vilanova's health, but the club cancelled all media duties scheduled for Wednesday - including the traditional Christmas media lunch - without giving reasons.
The club added that further communication would be made later in the day.
Barcelona-based sports newspaper El Mundo Deportivo claimed the decision was made following news of the health of coach Vilanova, who had a tumour removed last November.
It is understood that the tumour has recurred and that the 43-year-old will undergo treatment as soon as possible.
Some sources reported that he was already undergoing surgery at a local hospital.
The reports were confirmed by various reputable sources in Spain and elsewhere, although there has been no official announcement.
Vilanova is expected to step down temporarily with the club set to name an interim head coach.
He had only taken the job this season, following the decision of Pep Guardiola to quit and take a sabbatical from coaching.
Defender Eric Abidal was recently given the all-clear to return to training after his own battle with cancer, which saw him undergo a partial liver transplant.